kerrigan



Feb. a

INVE TOR ZWZ/c'an'? P ARK PLUG W. P. KERRIGAN Filed July 15 1922 RY WPatented Feb. 19, 1924.

UNITED STATES PATENT OFFICE.

SPARK PLUG.

Application filed July 15, 1922.

To all whom it may concem.

Be it known that 1, WILLIAM P. Kenm- GAN, a citizen of the United Statesof America, residing at Astoria, Queens County,

State of New York, have invented certain new and useful Improvements inSpark Plugs, of which the following is a specification.

This invention relates to improvements in spark plugs, which form partof the ignition mechanism of motor vehicles. One of the objects of myinvention is to improve spark plugs having in combination with the usualelectrodes a spark intensifying device. One of the objections to plugsof this nature is that the starting of a motor by hand cranking islaborious,'owing to the fact that the motor has to be spun at arelatively high speed in order that sufii-' cient electric current canbe generated to jump both gaps of the plug. The above pertains to motorshaving magneto ignition. Another objection to these plugs is that theyimpose additional strain upon spark coils.

2a or coil, in a battery ignition device, as current has to be pileddrain the condenser before the spark intensifying gap can be jumped, andthe greater the gpp the more the strain upon thecoi], there ing the coilby causing it to become overheate' One of the ob ects of my invention isto provide means whereby the spark intensifying gap will be bridgeduntil the motor has started, the gap will be discontinued until themotor is again stopped. When thesparkintensifying gap is bridged, theplugrwill function as an ordinary spark plug. o accomplish the abovementioned result, I employ a thermostatic bridge for the sparkintensifying gap, said bridge being operated to break the metalliccircuit between the electrodes of the lug by the heat of the plug whichwill become heated after operated a few minutes.

I will now proceed to describe my invention more in detail, the novelfeatures of which I will point out in the appended claims, referencebein had to the accompanying drawing, which illustrates a sectional viewof a spark-plug of the spark intensifying type having my improvementapplied thereto.

The plug herein illustrated is comprised of the separably connectedmetal body memy endanger-' after which the bridging of usual well knownmanner detailed structure of.

the motor has been Serial No. 575,247.

bers 1 and 2, the member 2 being threaded a 3 to engage threads in anopening in a cylinder-head, a portion of which is indicated by 4. Thebody member 1 is threaded at 5 to engage threads in a counterbore in thebody member 2. The body member 1 carries a casing 6 of insulatingmaterial which at its upper end carries an adjustable electrode 7, whichis connected by a wire 8 to a distributor (not shown) or in the case ofa one cylinder motor to a make-and-break device. A distributormake-and-break device, magneto or spark coil have not been illustrated,for the reason that they are well known, as well as the circuitstherefor. The body of the plug carries the usual porcelain insert 8which supports an electrode 9 to cooperate with an electrode 10 carriedby the body member 2. 11 indicates va glass bushing within the casing 6.The numeral 12 indicates the gap for intensifying the spark at gap 13.The electrode 7 is made adjustable so that gap 12- can be varied toadjust the spark. he electrode 7 is adjusted by screwingsame in or outto increase or decrease thefgap'12. My improvement comprises a device tobridge the gap 12 so that a metallic circuit between the electrodes 7and 9 can be established. The bridge member 14 is connected at one endto the electrode 9 (in this instance), 'n any manner to produce anelectrical connection. I have herein illustrated a cap 15 to which thebridge 14 is secured at 16, said cap engaging the threaded end of theelectrode 9. The bridge 14 is made up in the form of a thermostat in theby strips of metal having different coeflicients of expansion, the thebridge not being illustrated. When the motor is cold, the bridge 14will, at its free end, rest against electrode'Z; hence, there will be ametallic circuit connection between, the electrodes '7 and 9, at whichtime the plug will be similar to the usual spark-plug. When the gap 12is bridged, in manner described, the spark can be generated by handcranking. After the motor has been in operation for a while, the plugwill become heated, causing the bridge 14 to straighten and breakcontact with electrode 7 after which the spark gap 12 will function.When the bidge 14 straightens, it will contact with an adjustablethreaded stop 17, held in adjusted positions by a nut 18. The gap 19,between electrode intensifying ap,

17 and bridge 14, when the contact between said bridge and electrode 7is broken, will be the inaxirnurn gap. Shoul'd'the e'lectr'ode '7 beadjusted to produce a gap at 12, too wide for the safety of the coil,the gap 19 will become the spark intensifying gap; hence, gap 19 is asafety gap to prevent the burning out of a coil, should gap 12 be toogreat. The adjustable stop screw 17 enables one to obtain a desiredsafety gap 19., Wl1en the inotor cools off after havingbee'n stopped,"

thebridge 14 will again contactrwith the electrode 7 to establish ametallic circuit between electrodes 7 and '9.

lVhat'I desire to secure by Letters Pateiit is:

LIA spark I g y with its spark gapga' supplementarspa'rkintensifyinggap, andelectrical cohducti'ng thermostatically operated means arrangedto bridge said gap.

2. A spark with its'spark gap a supplemental spa k and thermtet 'tic toshort circuit the s parleinteiisify'iug ga 3. Aspark plug, with itsspark gap a tensi fying gap and thermostatic m'aiislto control theoperation of'tlie spark intensifygg p M 4. A spark plug,plin-ality'j'ojf spaced apart electrodes l:o',p'1'o'dii :e sparlc gaps,one of said gaps,Bei gJa -spai-kiintensifying gap, eend ccm meansconnect ing said electrodes gap when the Iugis cold, nd air if; breaksaid confide-" across the spark i'fi'te'n'- sifying ranged toautoniaticaf tion when the plug 'b camesheafieii.

5. A spark plug having a plurality of spaced apart fixed electrodes, anadjustable electrode adjacent one of said fixed electrodes also spacedtherefrom to provide a spark intensifying gap, and a thermostaticconductor carried by one of the fixed electrodes arranged to bear upon.the adjustable contact.

'6. A spark plug having a plurality of spaced apart fixed electrodes, anadjustable electrode adjacent one of said'fixed electrodes also spacedtherefrom to provide a spark intensifying gap, a thermostatic conductorcarried by one of the fixed electrodes arranged to bear upon theadjustable electrode and to breakthe circuit between the fixed electrodeand the adjustable electrode.

when the plug becomes heated.

7. A spark plug having a plurality of spaced apart fixed electrodes, anadjustable electrode adjacent one of said fixed electrodes also spacedtherefrom to provide a limit the movement plug having "in combinationplug having mathematics having in combination; su ieme'ntal sparkinareasmay spark intensifying gap, 0. thermostatic conductoi: carried by thefixed electrode arranged to bear upon the adjustable electrode, to breakthe circuit between the fixed electrode anduthe adjustable electrodewhen the plug becomes heated, and means to of the thermostaticconductor; away from the adjustable electrode to pi'o irlea safety sparkgap there between of predetermined Width.

A Spflrl p lug,having plurality of spaced 'apirt fike cl 'e'lectro'des,an adjustable electrode adjacent oneof said fixed electrodes la'lsospacedftherefrcin to provide a intensi lyin gap, a thermostaticconcai'rijd "bythe fixed electrode arran'ge 'tobea'r uponthe adj ustableelectrode, to.-br eak,the circuit between the fixed electrodlindftheadjustable electrode when the becijifieshea ted, and an adjustable sto pto lifmit t'lie Ii1'ovei nent of the thermostatic pen uctora vayfiom theadjustable eleiitrdtleip pi'bvide'a safety spark gap.

:{91 A"'pi ;k plug'having "a plurality of spaceda 'art electrodes, andan adjustable siembd adjaceht 'one of the fixed electrbdesahfdspaced-therefrom to provide an int'eriSi'fyiii arkgap, i11eans adjacentthe adjustable electrodejarra ged to be s aced afsafcty gap, should thea betwee thjfixed electrode and the adjustaifil electrode be too great.

,10, haying a plurality of an electrode adjustable relativ'e tanner;electrodes to provide a 'theiebetivee'n, and means adjustab erelative'to the adjustable electrode 7 spark gap, said means actifig'as"feo jfliiet'drtb jc nnecc the fixed electrodeiefnd the last namedadjustable eleccrode. i

11. ,A.s:pa'rk plug, electrodes spaced apart to revide an intensifyingspark gap, meaii'sfto bridge the gap when the plug is cold and arran edto -auto.-'naticall break contact When'the'plug becomes heated, and anzidjii's'tble stop to limit the movement of the 'gap'bridging device.

Ina spark plug, a plurality of fixed contacts'spacd apart to provide aspark gap, an adjustable electrode adjacent one of'the fixed'contacts,arranged for moven'in't towardor away from the fixed contact to provide:1 variable spark intensifying. device, and conducting means connectedwith 'the fixed contact but spaced from the adjustable contact toprovide a safety spark WILLIAM P. KERRIGAN.

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